Ram accelerator augmented drilling system

ABSTRACT

Systems for drilling or tunneling include an assembly for accelerating a projectile into a region of geologic material. An interaction between the projectile and the geologic material extends a borehole and forms debris. The debris may be reduced in size by moving the debris to a crushing device. The reduced-size debris is then moved toward the surface using fluid movement. Water jets or other types of devices may be used to cut or deform a perimeter of a region of geologic material before the projectile is accelerated to control the shape of the borehole and the manner in which debris is broken from the geologic material.

PRIORITY

The present application claims priority to the currently-pending UnitedStates provisional application for patent having the application Ser.No. 63/069,644, filed Aug. 24, 2020, titled “Ram Accelerator AugmentedDrilling System”. U.S. patent application 63/069,644 is incorporated byreference herein in its entirety.

INCORPORATION BY REFERENCE

The following United States patents and patent applications areincorporated by reference for all that they contain:

U.S. patent application Ser. No. 13/841,236, now U.S. Pat. No.9,500,419, filed on Mar. 15, 2013, titled “Ram Accelerator System”.

U.S. patent application Ser. No. 14/708,932, now U.S. Pat. No.9,458,670, filed on May 11, 2015, titled “Ram Accelerator System withEndcap”.

Unites States patent application Ser. No. 15/246,414, filed on Aug. 24,2016, now U.S. Pat. No. 10,344,534, titled “Ram Accelerator System withEndcap”.

U.S. patent application Ser. No. 14/919,657, filed on Oct. 21, 2015, nowU.S. Pat. No. 9,988,844, titled “Ram Accelerator System with Rail Tube”.

U.S. patent application Ser. No. 15/135,452, filed on Apr. 21, 2016, nowU.S. Pat. No. 10,697,242, titled “Ram Accelerator System with Baffles”.

U.S. patent application Ser. No. 15/340,753, filed on Nov. 1, 2016, nowU.S. Pat. No. 10,557,308, titled “Projectile Drilling System”.

U.S. patent application Ser. No. 15/698,549, filed on Sep. 7, 2017, nowU.S. Pat. No. 10,590,707, titled “Augmented Drilling System”.

U.S. patent application Ser. No. 15/348,796, filed on Nov. 10, 2016, nowU.S. Pat. No. 10,329,842, titled “System for Generating a Hole UsingProjectiles”.

U.S. patent application Ser. No. 15/871,824, filed on Jan. 15, 2018, nowU.S. Pat. No. 10,914,168, titled “System for Acoustic Navigation ofBoreholes”.

U.S. patent application Ser. No. 17/096,435, filed Nov. 12, 2020, titled“Projectile Augmented Boring System”.

BACKGROUND

Traditional drilling and excavation methods use drill bits to penetratethrough rock, dirt, and other geologic material to form boreholes, suchas for production of hydrocarbons, water wells, geothermal energy, andso forth. The efficiency of these methods may be limited depending onthe type of geologic material through which a drill bit penetrates. Forexample, a drill bit may progress more slowly through rock than softermaterials. These traditional methods require significant amounts ofenergy, water, and other materials to provide rotational force to drillbits, cool the drill bits during operation, stabilize the borehole, andremove cuttings and other materials produced during drilling operations.Traditional methods also cause wear on cutting surfaces and othercomponents, requiring replacement, which can slow or halt drillingoperations.

BRIEF DESCRIPTION OF FIGURES

The detailed description is set forth with reference to the accompanyingfigures.

FIG. 1 depicts an implementation of a system for extending a borehole byaccelerating one or more projectiles into a region of geologic materialand removing debris formed by an interaction between the projectile(s)and the geologic material.

FIG. 2 depicts an implementation of a system in which a conveying deviceis used to move debris created by an interaction between a projectileand geologic material toward a crushing device.

FIG. 3 depicts an implementation of a system in which a pre-conditioningdevice, such as a water jet, is integrated within a conveying device,such as an auger.

FIGS. 4A through 4G depict an implementation of a method for extending aborehole by accelerating one or more projectiles into a region ofgeologic material and removing debris from the borehole and system.

FIG. 5 is a diagram depicting an implementation of a projectile seatedwithin a conduit.

While implementations are described in this disclosure by way ofexample, those skilled in the art will recognize that theimplementations are not limited to the examples or figures described. Itshould be understood that the figures and detailed description theretoare not intended to limit implementations to the particular formdisclosed but, on the contrary, the intention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope as defined by the appended claims. The headings used in thisdisclosure are for organizational purposes only and are not meant to beused to limit the scope of the description or the claims. As usedthroughout this application, the word “may” is used in a permissivesense (i.e., meaning having the potential to) rather than the mandatorysense (i.e., meaning must). Similarly, the words “include”, “including”,and “includes” mean “including, but not limited to”.

DETAILED DESCRIPTION

Boreholes may be formed in geologic material for production ofhydrocarbons, water wells, geothermal energy, performance of miningoperations, or other purposes. A borehole may be a generally verticalshaft, a generally horizontal shaft, or an angled shaft. In some cases,the direction of a borehole may be changed as the borehole is extended,such as through use of directional drilling techniques. Conventionaloperations for forming and extending a borehole use rotary drill bits tobore through earth, rock, or other geologic materials. Motive force isapplied to the drill bit using motors or similar devices located at thesurface, or within the borehole, to cause the drill bit to rotate andpenetrate through geologic material, forming debris referred to ascuttings. Fluid from the surface, known as drilling mud, is flowedthrough drill pipe or another type of conduit into the borehole to cooland lubricate the drill bit. The drilling mud also washes the cuttingsfrom the bottom of the borehole and carries the cuttings toward thesurface, enabling drilling operations to continue. Conventional drillingoperations typically require large quantities of energy, water, andmaterials. For example, cutting surfaces of drill bits, as well as otherdownhole and surface equipment, may be subject to wear and requirerepair or replacement, during which drilling operations may be slowed orhalted. Additionally, large quantities of energy, water, and drillingmud may be necessary to apply rotative force to a drill bit, cool andlubricate the drill bit, and remove cuttings from a borehole. Further,the efficiency of drilling operations may be affected by variousenvironmental conditions, such as the composition of geologic material.For example, drilling through resistant material such as hard rock mayrequire greater amounts of energy and materials, cause greater wear toequipment, and extend a borehole at a slower rate than drilling throughother materials.

Described in this disclosure are systems for extending a borehole withingeologic material using interactions between projectiles and thegeologic material. A projectile may be positioned within a launch tubeor another type of conduit. An end of the launch tube may be orientedtoward a region of the geologic material where it is desired to createor extend a borehole. One or more propellant materials may be providedinto the launch tube or another conduit adjacent to the launch tube.Conduits between the launch tube and the surface may be used totransport projectiles, propellant material(s), or other materials fromthe surface to the launch tube. In some implementations, propellantmaterial(s) may be generated within a borehole, such as by providingmaterials into the borehole or using materials that occur within theborehole and one or more devices within the borehole to performelectrolysis or another type of reaction or process to generate thepropellant material(s). For example, electrolysis of water within theborehole may be used to form hydrogen and oxygen, which may be used aspropellant materials. Propellant materials may include one or morecombustible or detonatable materials that apply a force to a projectilewhen ignited, one or more pressurized materials such as compressed air,water, or other fluids that apply a force to the projectile based on thepressure of the material(s), and so forth. The force may accelerate theprojectile out from the launch tube and into contact with a region ofthe geologic material. In other implementations, the projectile may beaccelerated by applying an electromagnetic force in addition to or inplace of use of propellant materials to apply a pressure to theprojectile. The interaction between the projectile and the geologicmaterial may extend a borehole. Conduits between the launch tube and thesurface may also be used to control a pressure at the lower end of theborehole, such as by venting pressure or material from the borehole tothe surface, or providing fluids or other materials into the launch tubeor borehole to maintain a selected pressure.

In some implementations, the projectile may be formed having twoportions, such as a front and rear portion, and the rear portion may beremovable from (e.g., shearable or frangible from) the front portion.For example, the rear portion may have a diameter greater than that ofthe front portion to enable the projectile to be positioned within or atan end of the launch tube while the greater diameter of the rear portionprevents passage of the projectile before pressure is applied using thepropellant material(s). The rear portion may include an O-ring or othertype of sealing service that prevents passage of propellant material(s)or pressure from behind the projectile into the launch tube. The sealingmember and rear portion of the projectile may enable pressure from thepropellant material(s) to increase to a desired level before the rearportion is separated from the front portion, enabling the force from thepropellant material(s) to accelerate the front portion of the projectilethrough the launch tube. In some implementations, the front portion ofthe projectile may include an O-ring or sealing device that removesmaterial from the launch tube as the projectile is accelerated throughthe launch tube.

The interaction between the projectile and the geologic material maygenerate debris, such as by breaking portions of rock or other geologicmaterial from the region contacted by the projectile. In some cases, thedebris created by the interaction between the projectile and thegeologic material may be fairly large, and removal of the debris fromthe borehole using drilling mud, air, water, or another type of fluidmay be impractical. In such a case, a crushing device may be used toreduce a size of the debris. In some implementations, the crushingdevice may include a drill bit positioned at or near the end of thelaunch tube. Interactions between the drill bit and the debris mayreduce the size of the debris. A fluid within the borehole may then beused to move the debris having the reduced size through a conduit awayfrom the region of geologic material contacted by the projectile (e.g.,toward the surface), such as by entraining the debris, forming a slurry,and so forth. In other implementations, the crushing device may includea gyratory crusher, a jaw-type crusher, or another type of crushingdevice which may be positioned away from the bottom of the borehole,such as within a conduit oriented toward the debris. A conveying device,such as an auger, may move debris away from the bottom of the boreholeand toward the crushing device, which may reduce the size of the debrissuch that a fluid may move the debris having the reduced size toward thesurface. For example, a conveying device may be positioned in a secondconduit that is adjacent to, coaxial with, positioned within, orcontains a first conduit through which the projectile is accelerated. Instill other implementations, additional projectiles may be acceleratedinto contact with the debris to reduce the size of the debris in lieu ofor in addition to use of a separate crushing device.

In some implementations, a pre-conditioning device or material may beused to contact at least a portion of the perimeter of the region of thegeologic material where the projectile is accelerated. For example, awater jet, cutter, drill bit, or one or more initial projectileinteractions may be used to pre-condition a region of geologic materialby interacting with a perimeter of the region before a projectile isaccelerated into contact with the region. The pre-conditioned perimetermay control the manner in which the borehole is extended, such as bycontrolling the manner in which shock waves propagate through thegeologic material, which may be used to control the size and shape ofthe borehole, the formation of debris, and so forth.

In some implementations, sections of casing or another type of conduitmay be inserted into a borehole as the borehole is extended usingprojectiles and as debris is removed from the borehole. For example, ifdebris is removed from the borehole using an auger and crushing devicewithin a conduit, the annulus of the borehole may not necessarily beused for this purpose, and casing may be lowered into the annuluswithout interfering with the removal of debris from the borehole.

FIG. 1 depicts an implementation of a system 100 for extending aborehole 102 by accelerating one or more projectiles 104 into a regionof geologic material 106 and removing debris 108 formed by aninteraction between the projectile(s) 104 and the geologic material 106.Geologic material 106 may include earth, sand, aggregate, hard rock,porous or softer rock, or any other material within which a borehole 102may be formed. For example, a borehole 102 formed in rock or other typesof geologic material 106 may be used for production of hydrocarbons,water, geothermal energy, and so forth. While FIG. 1 depicts theborehole 102 as a generally vertical shaft, in other implementations, aborehole 102 may include a horizontal shaft, an angled shaft, or a shafthaving an irregular (e.g., non-straight) shape, such as a shaft thatincludes curves, angles, and so forth.

To extend the borehole 102, one or more projectiles 104 may beaccelerated through one or more conduits, such as a launch tube 110. Thelaunch tube 110 may include a pipe or other type of conduit having afirst end oriented toward a region of the geologic material 106, such asa distal end of the borehole 102, and a second end opposite the firstend. In some implementations, the first end of the launch tube 110 thatis oriented toward the geologic material 106 may include an open end. Inother implementations, the first end of the launch tube 110 may becovered by one or more endcaps 111, or one or more valves or other typesof separator mechanisms may seal at least a portion of the launch tube110 from an environment within the borehole 102 external to the launchtube 110. For example, at least a portion of the launch tube 110 may beisolated from pressure within the environment of the borehole 102external to the launch tube 110, and in some cases, the launch tube 110may also be isolated from ingress of material, such as debris 108,fluids, and so forth. In some implementations, at least a portion of thelaunch tube 110 may be isolated from pressure or materials within theborehole 102 by controlling a pressure of the portion of the launch tube110 or of the borehole 102. For example, one or more conduits may beused to vent pressure or other materials from a region of the borehole102 proximate to the first end of the launch tube 110, or to providematerials into the launch tube 110 proximate to the first end, such thatpressure in the launch tube 110 prevents ingress of pressure ormaterials from the region of the borehole 102 proximate to the first endof the launch tube 110. Techniques to control the pressure within theborehole 102 or launch tube 110 using conduits may be used in place ofor in addition to use of endcaps 111, valves, or other closure orseparation mechanisms that physically impede transmission of pressure ormaterials from the borehole 102 into the launch tube 110.

While the first end of the launch tube 110 is oriented toward thegeologic material 106, FIG. 1 depicts a breech tube 112 positioned atthe second end of the launch tube 110 opposite the first end to form acontiguous conduit. In some implementations, the launch tube 110 andbreech tube 112 may include separate members, while in otherimplementations, the launch tube 110 and breech tube 112 may include asingle member. The breech tube 112 may have a diameter larger than thatof the launch tube 110, while the launch tube 110 may have a diametersimilar to that of the projectile(s) 104 to facilitate the accelerationof the projectile(s) 104 through the launch tube 110 using pressure fromone or more propellant materials within the breech tube 112. Forexample, when a projectile 104 is loaded into the breech tube 112, theprojectile 104 may seat within a throat 114 between the breech tube 112and launch tube 110, the throat 114 constituting a region of narroweddiameter relative to that of the breech tube 112. In someimplementations, the throat 114 may include a separate member that isengaged to the launch tube 110 or breech tube 112. In otherimplementations, the throat 114 may be a unitary member with one or bothof the launch tube 110 or breech tube 112. The projectile 104 mayinclude one or more portions of increased diameter, sealing members, orshearable members such as a snap ring that may contact the innerdiameter of the throat 114 or of the launch tube 110 to prevent movementof the projectile 104 through the launch tube 110 until pressure fromthe propellant material(s) within the breech tube 112 is sufficient toshear or degrade the portion of increased diameter, sealing member, orshearable member. After the pressure has sheared or degraded at least aportion of the projectile, the pressure may cause the remainder of theprojectile to be accelerated through the launch tube 110 at sufficientvelocity to impact the geologic material 106, extend the borehole 102,and form debris 108.

For example, surface equipment 116 positioned at the surface 118 of theborehole 102 may transport projectiles 104, propellant materials, orother materials into the breech tube 112 via one or more propellantconduits 120, such as coiled tubing. In other implementations, thesurface equipment 116 may be located within the borehole 102. Forexample, one or more air compressors, tanks or other sources ofpropellant material, containers that contain projectiles 104, and soforth, may be positioned within the borehole 102 at a location wherematerials may be provided into the breech tube 112. In still otherimplementations, one or more materials used to accelerate the projectile104 may be generated within the borehole 102. For example, devices forperforming electrolysis on water or other fluids within the borehole 102may be used to generate hydrogen, oxygen, or other propellant materialswithin the borehole 102, eliminating the need to provide propellantmaterials using surface equipment 116 or downhole sources of propellantmaterials. Propellant material(s) may be provided to the breech tube 112to increase a pressure behind the projectile 104. Ignition of thepropellant material(s) or the pressure of the propellant material(s) mayimpart a force to the projectile 104 to force the projectile 104 pastthe throat 114 and accelerate the projectile through the launch tube110, out the first end of the launch tube 110, and into contact with thegeologic material 106 at the end of the borehole 102. In otherimplementations, an electromagnetic force may be used to accelerate theprojectile 104 in addition to or in place of pressure from propellantmaterials. In some implementations, passage of the projectile 104through the launch tube 110 may impart a ram effect to the projectile104, the launch tube 110 functioning as a ram accelerator. For example,interactions between the projectile 104 and one or more interiorfeatures of the launch tube 110, such as baffles, rails, or other typesof variations in the internal diameter of the launch tube 110, mayincrease the speed of the projectile 104 as it passes through the launchtube 110, in some implementations in combination with the force impartedto the projectile 104 using pressurized or combustible gas, or otherpropellant materials.

As described previously, interactions between projectiles 104 and thegeologic material 106 may form debris 108. In some cases, the sizes ofat least a portion of the debris 108 may be large enough to impairmovement of the debris 108 using fluid, such as drilling mud or otherfluids that may be provided into the borehole 102 to move the debris 108from the bottom of the borehole 102. In some implementations, one ormore crushing devices may be used to reduce the size of the debris 108.After reducing the size of the debris 108, the debris 108 that has beenreduced in size may be moved through use of drilling fluid, anotherfluid, or other sources of motive force. In some implementations, thecrushing device(s) may include use of one or more successive projectiles104, which may be accelerated through the launch tube 110 to interactwith at least a portion of the debris 108. Interaction between theprojectile(s) 104 and the debris 108 may reduce a size of the debris108, such as by breaking or otherwise degrading larger pieces of debristo form smaller pieces.

In other implementations, the crushing device(s) may include a drill bit122. For example, FIG. 1 depicts a drill bit 122 positioned at the firstend of the launch tube 110. The drill bit 122 may be moved into contactwith the debris 108, such as by lowering a drilling conduit 124, such asa drill pipe, to which the drill bit 122 is engaged. The drill bit 122may be rotated using rotational force imparted by movement of thedrilling conduit 124, such as through use of one or more motors or othersources of motive force located at the surface 118 or within theborehole 102. Interactions between the drill bit 122 and the debris 108may reduce a size of the debris 108, which may enable movement ofdrilling mud or other fluid to remove the debris 108 from the bottom ofthe borehole 102. For example, drilling fluid may be provided into theborehole 102 through the drilling conduit 124, such as to cool andlubricate the drill bit 122 during use, provide motive force, and soforth. The drilling fluid may entrain at least a portion of the debris108, such as by forming a slurry, then move the debris 108 away from thebottom of the borehole 102 and toward the surface 118, such as by movingup through an annular space 126 between the drilling conduit 124 and thewall of the borehole 102. In some implementations, the wall of theborehole 102 may include one or more sections of casing that may belowered into the borehole 102 as the borehole 102 is extended usingprojectiles 104 to displace geologic material 106. Because interactionsbetween the projectiles 104 and the geologic material 106 are used toextend the borehole 102, while the drill bit 122 is primarily used tocontact debris 108 and reduce the size thereof, wear on the drill bit122 and the force and energy required to operate the drill bit 122 maybe reduced when compared to conventional drilling operations. Forexample, using the techniques described herein, use of the drill bit 122to penetrate through hard rock may be omitted. Projectile impacts mayinstead be used to extend a borehole 102 while the drill bit 122 is usedto reduce the size of resulting debris 108. In some implementations, thedrill bit 122 may be used in addition to projectile impacts to extendthe borehole 102. For example, the drill bit 122 may be used to extendthe borehole 102 while a subsequent projectile 104 is being loaded andpropellant materials are being provided into the breech tube 112. Asanother example, the drill bit 122 may be used to advance the borehole102 through selected materials, such as earth or porous rock, whileprojectile impacts are used to advance the borehole 102 through hardrock. While FIG. 1 depicts the launch tube 110 positioned within andaligned with the longitudinal axis of the drilling conduit 124, in otherimplementations, the launch tube 110 and drilling conduit 124 mayinclude separate conduits. In still other implementations, the launchtube 110 may be positioned within the drilling conduit 124 at a locationthat is not aligned with the longitudinal axis of the drilling conduit124, such that projectiles 104 may be accelerated to impact regions ofgeologic material 106 that are not directly in front of the end of thedrilling conduit 124. For example, the orientation of the end of thelaunch tube 110 relative to the geologic material 106 may change as thedrilling conduit 124 is rotated, and the times at which projectiles 104are accelerated may be used to affect the portion of the geologicmaterial 106 that is impacted by the projectiles 104.

In some implementations, one or more crushing devices that arepositioned away from the first end of the launch tube 110 may be used.For example, FIG. 2 depicts an implementation of a system 200 in which aconveying device 202 is used to move debris 108 created by aninteraction between a projectile 104 and geologic material 106 toward acrushing device 204. The conveying device 202 and crushing device 204are shown within a conveyor conduit 206 positioned within a borehole102. The conveyor conduit 206 may include any type of pipe, tube,string, or other type of conduit, such as drilling pipe, casing, and soforth. In some implementations, a wall of the borehole 102 may functionas a conveyor conduit 206 and use of a separate conveyor conduit 206 maybe omitted. As described with regard to FIG. 1, one or more projectiles104 may be accelerated through one or more conduits, such as a launchtube 110, using one or more propellant materials, to cause theprojectile(s) 104 to exit the conduit(s) and interact with a region ofgeologic material 106. Interactions between the projectiles 104 and thegeologic material 106 may form debris 108, such as portions of rock oranother type of material that are broken from a working face of thegeologic material 106 by an impact or other type of interaction with aprojectile 104. The system 200 of FIG. 2 is shown having two launchtubes 110. A first launch tube 110(1) is shown extending centrallythrough (e.g., aligned with a longitudinal axis of) the conveyor conduit206, while a second launch tube 110(2) is shown positioned off-centerrelative to the longitudinal axis of the conveyor conduit 206. Adiverter 208, such as one or more valves or other movable components,may be used to control movement of projectiles 104 into the first launchtube 110(1) or second launch tube 110(2). While FIG. 2 depicts twolaunch tubes 110, any number of launch tubes 110 having any positionrelative to the conveyor conduit 206 may be used. For example,acceleration of a projectile 104 through different launch tubes 110 mayenable different regions of geologic material 106 to be affected bycontact with a projectile 104. Continuing the example, accelerating aprojectile 104 into a region of the geologic material 106 locateddirectly below the conveyor conduit 206, such as by using the firstlaunch tube 110(1), may be used to extend the borehole 102 in agenerally straight direction. Acceleration of a projectile 104 into aregion of geologic material 106 located below the second launch tube110(2) may be used to extend the borehole 102 in a curved or angleddirection, or to pre-condition a perimeter of a region of geologicmaterial 106 before impacting the region with a projectile 104accelerated through the first launch tube 110(1). In someimplementations, the second launch tube 110(2) may be movable, such asthrough rotation of the conveyor conduit 206 or another portion of thesystem, to enable the region of geologic material 106 below the secondlaunch tube 110(2) to be changed.

As described with regard to FIG. 1, in some cases, at least a portion ofthe debris 108 formed from the interaction between a projectile 104 andthe geologic material 106 may have a size that prevents movement of thedebris 108 using fluid. For example, at least a portion of the debris108 may include large pieces of rock that are broken from a working faceof the geologic material 106 due to an impact by a projectile 104. Aconveying device 202 may be used to move debris 108 away from the end ofthe borehole 102 and toward the crushing device 204. In someimplementations, as shown in FIG. 2, the conveying device 202 mayinclude an auger. For example, rotational movement of the auger may moveat least a portion of the debris 108 upward along the blades of theauger through the conveyor conduit 206 toward the crushing device 204.The crushing device 204 may crush the debris 108, reducing a sizethereof. In some implementations, a screen or other mechanism forlimiting the size of debris 108 conveyed using the auger may bepositioned at or near the base of the conveyor conduit 206. For example,pieces of debris 108 that are larger than a selected size may beretained within the borehole 102 so that a subsequent projectile impactmay reduce the size of the debris 108. The reduced-size debris 108 maythen be moved toward the crushing device 204 by the auger. One or moredebris outlets 210, or in some implementations, a portion of theconveyor conduit 206 above the crushing device 204, may be used to movethe debris 108 that is crushed by the crushing device 204 toward thesurface 118. For example, the crushing device 204 may include a gyratorycrusher that reduces the debris 108 to a fine-grained slurry that may beentrained within a fluid and transported toward the surface 118. Asdescribed previously, while FIG. 2 depicts the launch tubes 110 withinthe conveyor conduit 206, such as passing through openings with theblades of the auger, in other implementations, one or more launch tubes110 may be positioned within the conveyor conduit 206 adjacent to theconveying device 202, or external to the conveyor conduit 206. Becausethe debris 108 may be transported toward the surface 118 within theconveyor conduit 206, the annular space 126 between the conveyor conduit206 and the wall of the borehole 102 may be used for other purposes,such as lowering of casing into the borehole 102, providing materialsinto or removing materials from the borehole 102, and so forth. Forexample, the annular space 126 may accommodate coiled tubing or othertypes of conduits for providing propellant materials or projectiles 104to the launch tubes 110, providing water into the borehole 102 forformation of propellant material(s) using electrolysis, providing air oranother fluid into the borehole 102 to remove material from the launchtubes 110 or other portions of the system 200, and so forth.

In some implementations, the system 200 may include one or morepre-conditioning devices, such as water jets 212, that may accelerate apre-conditioning material, such as water, toward a portion of thegeologic material 106. For example, one or more conduits within theconveyor conduit 206 or annular space 126 may be used to convey water tothe waterjet(s) 212, or the waterjet(s) 212 may communicate with anothersource of water located within the borehole 102. In someimplementations, the water jets 212 may accelerate water, or anotherpre-conditioning material, into contact with at least a portion of aperimeter of the region of geologic material 106 to be impacted by theprojectile 104. Pre-conditioning the perimeter of a region of geologicmaterial 106 may control the manner in which shock waves caused byprojectile impacts propagate through the geologic material 106, enablingthe shape of the borehole 102 to be controlled as the borehole 102 isextended. For example, water from the water jet(s) 212 may be used topre-cut along at least a portion of the perimeter of the region ofgeologic material 106. Interactions between projectiles 104 and thepre-conditioned region of geologic material 106 may break, pulverize, orotherwise degrade the material, forming a section of the borehole 102having the shape of the pre-conditioned profile.

Use of water jets 212, or other mechanisms, to pre-condition or pre-cuta rock face or other geologic material 106 in a desired cross-sectionalshape may increase the rate at which the borehole 102 may be extendedand enable the borehole 102 to be provided with irregularcross-sectional shapes. For example, by using water jets 212 to form asquare or rectangular perimeter shape, or another desired shape for thecross-section of a portion of a borehole 102, the breakage of rock usingprojectile impacts may be controlled. The extension of the borehole 102and near-bore rock damage may be controlled by use of the water jets 212or other pre-conditioning techniques to create a gap, or a region ofweakened rock or rock having a different density. The region of the rockaffected by the water jets 212 or other device(s) may simulate a freeface reflection zone so that a shock wave caused by a projectile impactchanges from a compression wave to a tension wave, which pulls andbreaks the geologic material 106 along the perimeter defined by thepre-conditioned profile. For example, creation of a cut orpre-conditioned region of rock may provide a boundary zone whereprojectiles that impact rock within the pre-conditioned region create atension wave that is affected by the cut or weakened region of rock asdescribed above.

While FIG. 2 depicts pre-conditioning devices that include water jets212, in other implementations, other methods for pre-conditioning orcutting the geologic material 106 may be used. For example, rock sawblades, rotating cutters, disc cutters, road headers, water jets withadded abrasives, thermal spallation, thermal conditioning (e.g., heatingand breaking rock), plasma jet cutters, pre-drilling, and so forth maybe used in addition to or in place of water jet 212 heads topre-condition a desired profile. In some implementations, projectileimpacts may be used to pre-condition a perimeter of a region of geologicmaterial 106. For example, projectiles 104 may be accelerated using thesecond launch tube 110(2), or another launch tube 110 positionedexternal to the conveyor conduit 206, to impact at least a portion of aperimeter of a region of geologic material 106. Subsequent projectileimpacts from a projectile 104 accelerated using the first launch tube110(1) may then break or otherwise degrade geologic material 106 withinthe region defined by the pre-conditioning of the geologic material 106.

Additionally, while FIG. 2 depicts the system 200 including two waterjets 212, which may be positioned to accelerate pre-conditioningmaterial to different portions of the geologic material 106 usingarticulating heads or movement of the conveyor conduit 206, in otherimplementations, other numbers of water jets 212 or other types ofpre-conditioning devices may be used. Further, while FIG. 2 depicts thewater jets 212 positioned external to, and at the base of, the conveyorconduit 206, in other implementations, pre-conditioning devices may bepositioned at any location within the borehole 102. In someimplementations, one or more water jets 212 may be incorporated withinthe blades of the auger, which may orient the water jets 212 toward aperimeter of a region of the geologic material 106 as the auger rotates.

For example, FIG. 3 depicts an implementation of a system 300 in which apre-conditioning device, such as a water jet 212, is integrated within aconveying device 202, such as an auger. In the system 300 shown in FIG.3, a single launch tube 110 is positioned within the conveyor conduit206 at a location that is spaced apart from the longitudinal axis of theconveyor conduit 206. For example, rotation of the conveyor conduit 206,conveying device 202, or other portion of the system 300 may enable thelaunch tube 110 to be moved relative to the geologic material 106, suchas to orient the lower end of the launch tube 110 toward a selectedregion of the geologic material 106. One or more water jets 212 may beincorporated proximate to the lower end of the conveying device 202,which is shown in FIG. 3 as an auger. Conduits for flowing water to thewater jet(s) 212 may be incorporated within the blades of the auger,other portions of the conveying device 202, or within the conveyorconduit 206. As the auger rotates, water from the water jet(s) 212 mayinteract with at least a portion of a perimeter of a region of thegeologic material 106. Subsequently, a projectile 104 may be acceleratedthrough the launch tube to contact the region of the geologic material106. The pre-conditioned perimeter of the region may control the mannerin which the geologic material 106 within the region is affected byinteractions with one or more projectiles 104, such as by controlling ashape of a section of the borehole 102 as it is extended. Debris 108formed by the interaction between the projectile(s) 104 and the geologicmaterial 106 may be moved from the bottom of the borehole 102 throughthe conveyor conduit 206 by the conveying device 202, toward a crushingdevice 204 which may reduce a size of the debris 108. The reduced-sizeddebris 108 may be moved toward the surface 118 of the borehole 102 via adebris outlet 210 or the conveyor conduit 206, such as by using a fluidto entrain the debris 108. In some implementations, casing or othermaterials for supporting the integrity of the borehole 102 may bepositioned within the annular space 126 between the conveyor conduit 206and the wall of the borehole 102 while the conveyor conduit 206, or oneor more other conduits within the conveyor conduit 206, may be used totransport projectiles 104, propellant materials, water, air, otherfluids, and so forth.

FIGS. 4A through 4G depict an implementation of a method 400 forextending a borehole 102 by accelerating one or more projectiles 104into a region of geologic material 106 and removing debris 108 from theborehole 102 and system 100. As shown in FIG. 4A, at a first time T1, aprojectile 104 is inserted into a breech tube 112 of the system using aprojectile inserter 402. As described with regard to FIG. 1, the breechtube 112 may include a pipe or other type of conduit having a firstdiameter, which is engaged to a launch tube 110 having a second diametersmaller than that of the breech tube 112. A throat 114 between thebreech tube 112 and launch tube 110 may include a region of narrowingdiameter between the breech tube 112 and launch tube 110 where aprojectile 104 may be placed before accelerating the projectile 104through the launch tube 110. In other implementations, one or more ofthe breech tube 112, throat 114, or launch tube 110 may include a singlemember rather than separate components that are engaged together.

In some implementations, the projectile inserter 402 may include amechanical member, such as a rod or plunger, which may be extended toapply a mechanical insertion force 403 to the projectile 104 to move theprojectile 104 from a loading area associated with the projectile source404 into the breech tube 112. In other implementations, the projectileinserter 402 may use an insertion force 403 imparted by movement orpressure of fluid. The projectile source 404 may include a tank,container, or conduit in communication with the breech tube 112. In someimplementations, the projectile source 404 may include a loading areathat receives projectiles 104 from the surface 118 of the borehole 102,such as via coiled tubing or another type of conduit. Additionally, insome implementations, the projectile source 404 may include mechanicalmembers or conduits for receiving fluid to cause movement of projectiles104 into and from a position from which the projectile inserter 402 mayapply an insertion force 403 to move a projectile 104 into the breechtube 112.

In some implementations, an endcap 111 may be inserted into the launchtube 110 prior to insertion of the projectile 104. The endcap 111 may beengaged with the launch tube 110 using one or more external features ofthe endcap 111 or one or more interior features within the launch tube110. Placement of an endcap 111 may displace material within the launchtube 110 into the borehole 102 and isolate the launch tube 110 from theenvironment within the borehole 102, enabling gas or other materialwithin the launch tube 110 to be vented or otherwise removed from thelaunch tube 110. Isolation of the launch tube 110 from the borehole 102and venting of material from within the launch tube 110 may enable apressure within the launch tube 110 to be controlled and preventmaterial or pressure within the launch tube 110 from interfering withmovement of the projectile 104.

As described with regard to FIG. 1, various types of surface equipment116 may be used to provide propellant materials, projectiles 104, air,water, or other fluids or materials into the breech tube 112 or otherportions of the system 100. In other implementations, one or morecomponents of the surface equipment 116 may be located within theborehole 102 rather than at the surface 118 thereof. As shown in FIG.4A, the surface equipment 116 may include a compressor 406 which may beused to provide air or another compressed or pressurized fluid intovarious portions of the system 100, such as for cooling portions of thesystem 100, moving debris 108 away from one or more portions of thesystem 100, or moving other materials into or from various portions ofthe system 100. The surface equipment 116 may also include a propellantsource 408 which may include one or more tanks, containers, or othersources of materials that may be used to apply a force to a projectile104 to accelerate the projectile 104 through the launch tube 110. Insome implementations, the propellant material(s) may include hydrogengas. In other implementations, the propellant material(s) may includeoxygen or other types of fluids. One or more mixers 410 or other typesof equipment may be used to combine air or another fluid from thecompressor 406 with one or more propellant materials from the propellantsource 408. The mixer 410 may be controllable to select a ratio ofmaterial from the propellant source 408 and material from the compressor406 to provide to a flow controller 412. The flow controller 412 mayprovide material from the mixer 410 into the breech tube 112 at aselected rate. In some implementations, the flow controller 412 mayinclude an igniter, or a separate igniter device may be associated withthe breech tube 112 or the surface equipment 116, which may be used toignite one or more propellant materials to provide a force to theprojectile 104. One or more pressure gauges 414 may be used to determinea pressure associated with propellant materials, or other materials, inthe flow controller 412 or breech tube 112. For example, pressure gauges414 may be used to determine whether the pressure of propellantmaterials in the breech tube 112 is sufficient to ignite the propellantmaterials to accelerate a projectile 104, or whether the pressure ofother materials in the breech tube 112 or another portion of the system100 is sufficient to vent or evacuate material from the system 100. Forexample, the system 100 may include one or more vents 416 which may beused to evacuate air, propellant material(s), or other fluids ormaterials from the launch tube 110 or other portions of the system 100.

As shown in FIG. 4B, at a second time T2, the projectile 104 may bemoved to the throat 114 using air or other fluids, which may impart afluid force 418 to the projectile 104. For example, after the projectileinserter 402 is used to move a projectile 104 from the projectile source404 into the breech tube 112, a fluid force 418 imparted by air oranother fluid from the compressor 406, or in some implementations, oneor more propellant materials from the propellant source 408, may be usedto move the projectile 104 through the breech tube 112. The projectile104 may include a portion having a diameter greater than that of thelaunch tube 110, such as a snap ring or other type of shearable,frangible, or deformable portion, such that the projectile 104 is seatedin the throat 114 between the breech tube 112 and launch tube 110 whenmoved using the fluid. Until pressure within the breech tube 112 issufficient to cause the shearable, frangible, or deformable portion ofthe projectile 104 to be removed from the projectile 104 or deformed toreduce a diameter of the projectile 104, the reduced diameter of thelaunch tube 110 may prevent further movement of the projectile past thethroat 114 and through the launch tube 110.

As shown in FIG. 4C, at a third time T3, air or other fluid(s) may beremoved from the breech tube 112 after positioning the projectile 104 inthe throat 114. For example, the breech tube 112 may be at leastpartially evacuated, or the pressure in the breech tube 112 may beotherwise reduced. Continuing the example, removed fluids 420 may beflowed from the breech tube 112 to one or more vents 416 associated withthe surface equipment 116 or with the breech tube 112 itself. Theremoved fluids 420 may include the air or other materials from thebreech tube 112 that were used to move the projectile 104 into thethroat 114, or that may otherwise remain in the breech tube 112 fromprevious operations, such as acceleration of a previous projectile 104.In some implementations, air or other fluid(s) may be removed from thelaunch tube 110 in addition to or in place of removal of air or fluid(s)from the breech tube 112.

As shown in FIG. 4D, at a fourth time T4, propellant material(s) 422 maybe provided into the breech tube 112. As described previously, in someimplementations, propellant material(s) 422 may include one or more ofhydrogen or oxygen. In other implementations, propellant material(s) 422may include one or more other combustible gasses or gasses that are ableto be pressurized to a pressure sufficient to accelerate the projectile104 through the launch tube 110. In some implementations, in-situpropellant material(s) 422 may be used. For example, a propellantmaterial 422 may be created using one or more devices for performingelectrolysis within the breech tube 112, or created in another portionof the system 100 and flowed into the breech tube 112. As anotherexample, propellant material(s) 422 may be entrained in drilling mud orother fluid, enabling transport of the propellant material(s) 422 intothe borehole 102 in the same fluid conduit as those used to transportthe drilling mud or other fluid. In some implementations, a portion ofthe material of the projectile 104, itself, may include a fuel orpropellant that may be combusted or pressurized. As one or morepropellant materials 422 are provided into the breech tube 112, one ormore pressure gauges 414 may be used to determine the pressure orconcentration of the propellant material(s) 422. A sealing member of theprojectile 104 may interact with the throat 114, launch tube 110, orbreech tube 112 to prevent passage of propellant material(s) into thelaunch tube 110, enabling the pressure of the propellant material(s) 422in the breech tube 112 to increase as one or more additional propellantmaterials 422 are provide into the breech tube 112.

As shown in FIG. 4E, at a fifth time T5, debris 108 may be flushed fromthe system 100 using air or other flushing fluids 424. For example, thecompressor 406 or another source of air or other flushing fluid(s) 424may be in communication with a drilling conduit 124 that is used torotate and provide fluid to a drill bit 122 at or near the end of thelaunch tube 110. In some implementations, the breech tube 112 and launchtube 110 may be positioned within the drilling conduit 124. In otherimplementations, the breech tube 112 and launch tube 110 may be aseparate conduit outside of the drilling conduit 124. Additionally,while FIGS. 4A through 4G depict the drill bit 122 near the end of thelaunch tube 110, in other implementations, the drill bit 122 may be nearthe end of the borehole 102, while the end of the launch tube 110 may bespaced farther from the bottom of the borehole 102. For example, aprojectile 104 may be accelerated through the launch tube 110 and mayexit the launch tube 110 at a selected distance from a working face ofthe geologic material 106.

Air or other flushing fluid(s) 424 from the compressor 406 that areflowed through the drilling conduit 124 may remove debris 108, fluid, orother material from the drilling conduit 124, drill bit 122, bottom ofthe borehole 102, launch tube 110, and annular space 126 between thedrilling conduit 124 and wall of the borehole 102. For example, air maybe flowed through the drilling conduit 124 toward the bottom of theborehole 102, where the air may push debris 108 or other material upwardand out of the borehole 102 through the annular space 126. In otherimplementations, air or other flushing fluid(s) 424 may be provided intothe annular space 126, and debris 108 or other material moved by the airor other flushing fluid(s) 424 may move out of the borehole 102 throughthe drilling conduit 124. In cases where a drill bit 122 is not used,air may be flowed into or from the borehole 102 using other conduits orthe annular space 126 independent of a drill bit 122.

As shown in FIG. 4F, at a sixth time T6, the breech tube 112 may beisolated and one or more propellant materials may be ignited toaccelerate the projectile 104 through the launch tube 110. As describedpreviously, a sealing member of the projectile 104 may cause theprojectile 104 to interact with the throat 114, launch tube 110, orbreech tube 112 to prevent passage of propellant material(s) from thebreech tube 112 into the launch tube 110, effectively isolating thebreech tube 112 from the launch tube 110. One or more valves, seals, orother types of closure or sealing mechanisms may be used to isolate thebreech tube 112 from the projectile source 404, flow controller 412, orother conduits in communication with the breech tube 112. Isolation ofthe breech tube 112 may enable the majority of the pressure associatedwith ignition of the propellant material(s) to apply a propellant force426 to the projectile 104. The propellant force 426 applied to theprojectile 104 may cause a snap ring or other shearable, frangible, ordeformable portion of the projectile 104 to be removed or deformed,enabling the projectile 104 to pass from the throat 114 into the launchtube 110, moving from an initial position 428 within the throat 114 to atarget position 430 where the projectile 104 may interact with a regionof geologic material 106. Propellant force 426 from the propellantmaterial(s) may continue to accelerate the projectile 104 through thelaunch tube 110. In some implementations, passage of the projectile 104through the launch tube 110 may impart a ram effect to the projectile104, the launch tube 110 functioning as a ram accelerator. For example,interactions between the projectile 104 and one or more interiorfeatures of the launch tube 110, such as baffles, rails, or other typesof variations in the internal diameter of the launch tube 110, mayincrease the speed of the projectile 104 as it passes through the launchtube 110. The projectile 104 may exit the end of the launch tube 110 tointeract with a region of the geologic material 106 and extend theborehole 102. In some implementations, the projectile 104 may passthrough one or more valves, endcaps 111, or separator mechanisms withinthe breech tube or launch tube. In some cases, the projectile 104 maypenetrate through these components, and the components may be replaced,such as by inserting subsequent components into the launch tube 110 orbreech tube 112 using the projectile inserter 402, movement of fluid, orother techniques. In other cases, one or more of such components may beopened or moved from the path of the projectile 104 before acceleratingthe projectile 104 through the launch tube 104. In some implementations,a sealing member or other component of the projectile 104 may contact orextend close to the inner diameter of the launch tube 110, such thatpassage of the projectile 104 through the launch tube 110 removes debris108, fluid, or other material from the launch tube 110. Interactionbetween the projectile 104 and the region of geologic material 106impacted by the projectile 104 may create debris 108.

As shown in FIG. 4G, at a seventh time T7, debris 108 may be crushedusing the drill bit 122 or another crushing device, the debris 108 maybe flushed and the system 100 cooled using air or other flushing fluids424, and a subsequent projectile 104 may be prepared for insertion. Forexample, after the interaction between the projectile 104 and the regionof geologic material 106 forms debris 108, the drill bit 122 may contactand crush at least a portion of the debris 108, reducing a size of thedebris 108. In other implementations, the debris 108 may be crushed orotherwise reduced in size by moving the debris 108 using a conveyingdevice 202, such as an auger, toward a crushing device 204 locatedwithin a conduit, such as a gyratory crusher. In still otherimplementations, the debris 108 may be reduced in size by an interactionwith a subsequent projectile 104. For example, the method 400 shown inFIGS. 4A through 4G may be repeated, and a projectile 104 that impactsthe debris 108 may reduce the size of the debris 108. The compressor 406or another source of air or another fluid may be used to provide the airor other fluid into the drilling conduit 124 to move the debris 108. Theair or other flushing fluid 424 may move debris 108 that has beenreduced in size toward the surface 118. In other implementations,drilling fluid may be provided into the drilling conduit 124, such as tocool and lubricate the drill bit 122, and the drilling fluid may entrainand move debris 108 toward the surface 118. For example, air, drillingfluid, or one or more other fluids may move debris 108 toward thesurface via the annular space 126. In other implementations, air ordrilling fluid may be provided into the annular space 126 and thefluid(s) and debris 108 may move toward the surface 118 through thedrilling conduit 124. In still other implementations, debris 108 may bemoved toward the surface 118 using one or more debris outlets 210associated with a crushing device 204, as shown in FIG. 2. After theseventh time T7, the method 400 shown in FIGS. 4A through 4G may berepeated, and a subsequent interaction between a projectile 104 andgeologic material 106 may be used to further extend a borehole 102.

As described previously with regard to FIGS. 2 and 3, in someimplementations, a pre-conditioning device, such as one or more waterjets 212, cutters, drills, projectile impacts, and so forth may be usedto provide a pre-conditioning material into contact with at least aportion of a perimeter of a region of geologic material 106 before aprojectile 104 is accelerated through the launch tube 110 to impact theregion of geologic material 106. For example, after performing the stepshown in FIG. 4G, during performance of any of the steps shown in FIGS.4A through 4E, or before performing the step shown in FIG. 4F, apre-conditioning material may be accelerated into contact with thegeologic material 106 to prepare a perimeter of a region of the geologicmaterial 106 prior to an interaction with a projectile 104.

FIG. 5 is a diagram 500 depicting an implementation of a projectile 104seated within a conduit. As described with regard to FIGS. 1-4, aprojectile 104 may be moved through a breech tube 112 to be seated at athroat 114 between the breech tube 112 and a launch tube 110. Pressureassociated with propellant materials provided to the breech tube 112 maythen be used to accelerate the projectile 104 through the launch tube110. The launch tube 110 and at least a portion of the throat 114 mayhave a narrower diameter than that of the breech tube 112. For example,the throat 114 may include a tapered region 501 that connects a firstportion of the throat 114 having a diameter similar to that of thebreech tube 112 to a second narrower portion of the throat 114 having adiameter similar to that of the launch tube 110. The narrower diameterof the throat 114 and launch tube 110 may enable the projectile 104 tobe retained in the throat 114 until pressure in the breech tube 112 issufficient to force the projectile 104 into the launch tube 110, suchhas by shearing, removing, breaking, or deforming a portion of theprojectile 104 having a diameter greater than that of the launch tube110.

The projectile 104 is shown having a generally cylindrical body, howeverin other implementations, projectiles 104 having any shape that is ableto be moved within the launch tube 110 may be used. The body of theprojectile 104 may be formed from metal, plastic, composite, concrete,or other materials. In some implementations, the projectile 104 may beformed using an additive fabrication process. In some implementations,the projectile 104 may include one or more recessions 502, such asbores, pockets, or other recessed regions or compartments, which may beused to contain sensors or other instrumentation, magnetic materialsthat may facilitate movement or sensing of the projectile 104,combustible or detonatable materials, propellant materials, and soforth. While FIG. 5 depicts a generally cylindrical recession 502located within the front of the projectile 104, any number of recessions502 having any shape may be located in any portion of the body of theprojectile 104, or the projectile 104 may lack recessions 502.Additionally, while FIG. 5 depicts the body of the projectile 104 as asingle piece, in other implementations, the projectile 104 may includemultiple pieces that are joined together.

A front sealing member 504 may be positioned proximate to a front end ofthe projectile 104. In some implementations, the front sealing member504 may include one or more O-rings, however, other types of sealingmembers or deformable materials may be used in other implementations.The front sealing member 504 may contact an inner diameter of the launchtube 110 as the projectile 104 moves through the launch tube 110. Thefront sealing member 504 may enable movement of the projectile 104through the launch tube 110 to remove fluid, debris 108, or othermaterials from the launch tube 110 as the projectile 104 is acceleratedthrough the launch tube 110. For example, the front sealing member 504may prevent debris 108 or other material within the launch tube 110 frompassing to the region of the launch tube 110 behind the projectile 104as the projectile 104 moves through the launch tube 110. In someimplementations, use of the front sealing member 504 may be omitted.

A rear sealing member 506 may be positioned proximate to a rear end ofthe projectile 104. The rear sealing member 506 may include one or moreof the types of sealing members described with regard to the frontsealing member 504. In some implementations, the front sealing member504 and rear sealing member 506 may include the same types of sealingmembers, while in other implementations, the front sealing member 504and rear sealing member 506 may include different types of sealingmembers. The rear sealing member 506 may contact an inner diameter ofthe breech tube 112 or throat 114 when the projectile 104 is seatedproximate to the end of the launch tube 110. A seal between the rearsealing member 506 and the conduit within which the projectile 104 isseated may prevent the passage of propellant material(s) from the breechtube 112 and portion of the throat 114 behind the projectile toward thefront of the projectile 104. As a result, the seal provided by the rearsealing member 506 may enable pressure associated with the propellantmaterial(s) within the breech tube 112 to be increased until thepressure is sufficient to force the projectile 104 into the launch tube110, such as by deforming, degrading, or shearing at least a portion ofthe rear sealing member 506 from the projectile 104.

In some implementations, the projectile 104 may include a removableportion 508 having a greater diameter than the remainder of the body ofthe projectile 104. For example, the removable portion 508 may have adiameter greater than that of the launch tube 110 to prevent passage ofthe projectile 104 into the launch tube 110 until a pressure associatedwith the propellant material(s) applies a force to the projectile 104that is sufficient to cause removal (e.g., shearing or breakage) ordeformation of the removable portion 508. In some implementations, theremovable portion 508 may include a snap ring that may be broken orsheared as pressure from the propellant material(s) forces theprojectile 104 through the throat 114 and into the launch tube 110. Inother implementations, the removable portion 508 may include a portionof the body of the projectile 104 that is frangible, breakable, ordeformable. In still other implementations, use of a removable portion508 may be omitted, and the rear sealing member 506 may function toretain the projectile 104 from passing through the launch tube 110 untilpressure from the propellant material(s) is sufficient to causedeformation or shearing of the rear sealing member 506. In someimplementations, the projectile 104 my include a coating, such as adeformable or shearable material. The coating may form a seal betweenthe throat 114 and the projectile 104, while also preventing passage ofthe projectile 104 through the throat 114 until pressure associated withthe propellant material(s) applies a force sufficient to shear, break,or otherwise deform the coating. For example, use of a coating materialmay perform the functions of both the rear sealing member 506 and theremovable portion 508, and use of a separate rear sealing member 506 andremovable portion 508 may be omitted.

While implementations are described in this disclosure by way ofexample, those skilled in the art will recognize that theimplementations are not limited to the examples or figures described. Itshould be understood that the figures and detailed description theretoare not intended to limit implementations to the particular formdisclosed but, on the contrary, the intention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope as defined by the appended claims. The headings used in thisdisclosure are for organizational purposes only and are not meant to beused to limit the scope of the description or the claims. As usedthroughout this application, the word “may” is used in a permissivesense (i.e., meaning having the potential to) rather than the mandatorysense (i.e., meaning must). Similarly, the words “include”, “including”,and “includes” mean “including, but not limited to”.

Although certain steps have been described as being performed by certaindevices, processes, or entities, this need not be the case and a varietyof alternative implementations will be understood by those havingordinary skill in the art.

Additionally, those having ordinary skill in the art readily recognizethat the techniques described above can be utilized in a variety ofdevices, environments, and situations. Although the present disclosureis written with respect to specific embodiments and implementations,various changes and modifications may be suggested to one skilled in theart and it is intended that the present disclosure encompass suchchanges and modifications that fall within the scope of the appendedclaims.

What is claimed is:
 1. A system comprising: a projectile assemblycomprising: a first launch tube having a first end oriented toward aregion of geologic material; a first projectile within the first launchtube; a first propellant material within the first launch tube, whereinignition of the first propellant material applies a force to the firstprojectile to accelerate the first projectile out from the first launchtube and into contact with the region of the geologic material to extenda borehole within the geologic material, and wherein an interactionbetween the first projectile and the geologic material generates debrisproximate to the region of the geologic material, and at least a portionof the debris has a first size that at least partially impedes movementof the debris using a fluid; and a crushing assembly comprising: acrushing device within the borehole, wherein the crushing device reducesthe at least a portion of the debris from the first size to a secondsize; and a first conduit within the borehole, wherein the fluid withinthe first conduit moves the at least a portion of the debris having thesecond size away from the region of geologic material.
 2. The system ofclaim 1, wherein the projectile assembly further comprises: a secondconduit that extends from an upper end of the borehole toward the firstlaunch tube for transporting one or more of: the first projectile, thefirst propellant material, or one or more components to generate thefirst propellant material.
 3. The system of claim 1, wherein theprojectile assembly further comprises a device for performingelectrolysis within the borehole, wherein interaction between the deviceand one or more materials within the borehole forms at least a portionof the first propellant material using an electrolysis process.
 4. Thesystem of claim 1, wherein the crushing device comprises a drill bitlocated at the first end of the first launch tube.
 5. The system ofclaim 1, wherein the first launch tube has a second end opposite thefirst end, and the crushing device is positioned within the boreholecloser to the second end than the first end.
 6. The system of claim 5,further comprising a conveying device having a first end positioned inassociation with the crushing device and a second end positionedproximate to the region of geologic material, wherein the conveyingdevice moves the at least a portion of the debris having the first sizefrom a first location proximate to the second end of the conveyingdevice to a second location toward the crushing device.
 7. The system ofclaim 1, further comprising one or more third devices within theborehole and oriented to accelerate a pre-conditioning material intocontact with at least a portion of a perimeter of at least a portion ofthe region of the geologic material, wherein an interaction between thepre-conditioning material and the region of the geologic material causesthe interaction between the first projectile and the geologic materialto generate the debris from the at least a portion of the region withinthe perimeter.
 8. The system of claim 7, wherein the one or more thirddevices comprise one or more water jets.
 9. The system of claim 7,wherein the one or more third devices comprise: a second launch tubehaving an end oriented toward the at least a portion of the perimeter; asecond projectile within the second launch tube; and a second propellantmaterial within the second launch tube, wherein ignition of the secondpropellant material applies a force to the second projectile toaccelerate the second projectile out from the second launch tube andinto contact with the at least a portion of the perimeter.
 10. A methodcomprising: accelerating a projectile into contact with a region ofgeologic material to extend a borehole, wherein an interaction betweenthe projectile and the geologic material forms debris having a firstsize that at least partially impedes movement of the debris away fromthe region of geologic material; crushing the debris with a crushingdevice to reduce the debris from the first size to a second size; andmoving the debris having the second size away from the region ofgeologic material.
 11. The method of claim 10, wherein accelerating theprojectile comprises: positioning the projectile within a tube having afirst end oriented toward the region of the geologic material; providinga propellant material to a second end of the tube opposite the firstend, wherein the projectile is positioned between the propellantmaterial and the first end; and igniting the propellant material toapply a force to the projectile to accelerate the projectile toward thefirst end.
 12. The method of claim 10, further comprising using aconveying device to move the debris having the first size away from theregion of the geologic material and toward the crushing device.
 13. Themethod of claim 10, wherein moving the debris having the second sizeaway from the region comprises: providing a fluid into the borehole,wherein the fluid one or more of: applies a force to the debris havingthe second size or entrains the debris having the second size; andmoving the fluid away from the region of the geologic material.
 14. Themethod of claim 10, further comprising accelerating a pre-conditioningmaterial into contact with at least a portion of a perimeter of theregion of geologic material, wherein the interaction between theprojectile and the geologic material forms the debris from at least aportion of the region within the perimeter.
 15. A system comprising: afirst conduit having a first end and a second end opposite the firstend; a first projectile; a first propellant material, wherein the firstpropellant material applies a force to the first projectile toaccelerate the first projectile into contact with a region of geologicmaterial, and an interaction between the first projectile and thegeologic material generates debris having a first size that at leastpartially impedes movement of the debris; and a crushing device, whereinthe crushing device reduces the debris having the first size to formdebris having a second size smaller than the first size.
 16. The systemof claim 15, wherein the crushing device is positioned in a secondconduit, the system further comprising a conveying device within thesecond conduit, wherein the conveying device moves at least a portion ofthe debris having the first size toward the crushing device.
 17. Thesystem of claim 15, further comprising a third device to accelerate apre-conditioning material to contact at least a portion of a perimeterof the region of the geologic material, wherein the interaction betweenthe first projectile and the geologic material forms the debris havingthe first size from at least a portion of the region within theperimeter.
 18. The system of claim 15, further comprising a secondconduit extending between an upper end of a borehole and a portion ofthe borehole proximate to the first end of the first conduit, whereinthe second conduit one or more of: moves a first material from theportion of the borehole toward the upper end to reduce a pressureassociated with the portion of the borehole, or moves a second materialtoward the portion of the borehole from the upper end to increase apressure associated with the first conduit relative to the portion ofthe borehole.
 19. The system of claim 15, wherein the first projectilecomprises: a first portion having a first diameter less than or equal toa diameter of the first conduit; a second portion having a seconddiameter greater than the diameter of the first conduit, wherein thesecond portion is removable from the first portion; and a first sealingdevice associated with the second portion, wherein an interactionbetween the first sealing device and the first conduit causes pressureassociated with the first propellant material to increase to a thresholdpressure, and wherein application of the threshold pressure to thesecond portion of the first projectile causes the second portion to beremoved from the first portion and acceleration of the first portiontoward the region of the geologic material.
 20. The system of claim 19,wherein the first projectile further comprises: a second sealing deviceassociated with the first portion, wherein an interaction between thesecond sealing device and the first conduit removes material from aninterior of the first conduit while the first portion moves through thefirst conduit.